Reports of a Bugatti sedan starting churning through the internet rumor mill back in 2006, but it looks as though the super saloon from the French automaker could finally surface at this September's Frankfurt Motor Show.

An invitation to Bugatti's 100th birthday party at the Frankfurt show appears to tease an all-new model from the Volkswagen-owned supercar maker. The supposed teaser shot only reveals the rear-end of a mystery model -- making it impossible to definitively say the car in question is a Bugatti-badged four-door - but the unwavering rumors seem to indicate it's highly plausible that a new Bugatti model is on tap for the Frankfurt show.

However, that being said, it's still possible that the car in question could be a successor for the Veyron supercar. Although they Veyron is only four years old, a number of hyper cars have entered the market since 2005, intruding on the Veyron's natural place it the market. Just as the Veyron trumped everything in production back in 2005, Bugatti could be looking for a repeat performance in the near future.

Then again, the invitation could just reveal another variation of the current Veyron. The press was abuzz about the prospect of a new Bugatti model just before last year's Geneva Motor Show, but the model in question turned out to be a two-tone blue version of the standard Veyron.